Unified helmet and oxygen breathing assembly



Jan. 9, 1968 J. R. FLEA-41N@ TAL 3,362,403

UNIFIED IfIE-JMEI' ANS@ OXYGEN BREATHING ASSEMBLY -Filed Dec. 11, 1965 I 5 Sheets-.Sheet 1 Jan. 9, 1968 J. R. FLEMING ETAL 3,362,403

UNIFlED HELMET AND OXYGEN BREATHING ASSEMBLY Filed Dec. 11, 196s 5 sheets-sheet `2' Jan- 9, 1968 J. R. FLEMING ETAL 3,362,403

UNIFIED HELMET AND OXYGEN BREATHING ASSEMBLY Filed Dec. l1, 1965 5 Sheets-Sheet 5 Jan. 9, 1968 J. R. FLEMING ETAL 3,362,403

UNIFIED HELMET AND OXYGEN BREATHING ASSEMBLY 4Filed Deo. 11, 196s .s sheets-sheet 4 3y fon/gef AfA/0555 Jam 9 1968 J. R. FLEMJQNG ETAL 3,362,493

UNIFIED HELMET AND OXYGEN BREATHING ASSEMBLY l Filed Dec, 11, 196s f 5 sheds-sheet a f :53' Il I i' United States Patent O 3,362,403 UNIFIED HELMET AND OXYGEN BREATHING ASSEMBLY Lldhn R. Fleming, Long Beach, and Edward D. Nez, Pomona, Calif., assignors, by mesne assignments, to Rohertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed Dec. 11, 1963, Ser. No. 329,924 18 Claims. (Cl. 12d- 142) The present invention relates to an improved protective helmet assembly for pilots of high-speed, high altitude aircraft, and, more particularly, to a helmet assembly having an integral oxygen breathing assembly.

Protective helmet assemblies `of the prior art may be broadly classified as those comprising part of a full .or partial pressure suit and those having an open facial area partially covered by separate goggles and oxygen mask. Flight altitudes in excess of 50,000 feet require a pressure suit for pilot protection in the event of emergency decompression. Such a garment, however, is fatiguing and unnecessary for flights that can be accomplished at cabin altitudes under 45,000 feet. During such flights, adequate protection can be provided by a helmet system only. Since relative discomfort and fatigue are such that pilots strongly prefer to wear the minimum of equipment necessary to their particular mission, it is highly desirable that a choice of alternative equipment be provided for use on flights not requiring the bulky pressure suit.

Contemporary helmet designs with separate mask assemblies do not offer positive assurance of emergency oxygen for pilot ejection at Mach Il speeds since the high velocity air stream tends to tear loose the exposed oxygen mask. Moreover, the open-faced configuration of the helmet does not Offer protection from flash burns upon the exposed facial areas on ejection from supersonic seats.

Accordingly, an .object of the present invention is to provide a unified protective helmet and oxygen breathing system offering positive assurance of emergency oxygen and facial protection when ejecting at Mach II speeds.

Another object of the invention is to provide a protective helmet and integral oxygen breathing system which lits a substantial majority of pilots, i.e. those between the th and 95th percentile, thereby substantially reducing the number of different sized helmets required to iit every pilot. t

A further object of the invention is toV provide a protective helmet offering substantially increased peripheral vision for the pilot and decreased VCO2 concentration in the oral-nasal cavity.

Still another object of the invention is to provide a comfortable helmet which is self ventilated by the respiratory exhaust.

An additional object of this invention is to provide an improved face seal member conformable to wide facial variations.

Other and further objects, featuresvand advantages of the invention will become apparent as the description proceeds.

Briey, in accordance with a preferred form of the present invention, a protective helmet comprises an outer, two-piece shell generally shaped to lit the human head. The two shell halves are hinged together at the top to provide a clam shell entry. A lower opening formed in the shell receives the wearers neck. This opening is substantially smaller than the wearers head, making l-oss of the helmet during emergency ejection virtually impossible. V v

A full-face opening is surrounded .on the inner side of the helmet by a flexible face seal which engages the periphery of the wearers face. A transparent Vvisor may be 3,362,403 Patented Jan. 9, 1968 ICC lowered into position in front of the opening thereby transforming the space between the face seal and the transparent visor into an .oral-nasal cavity. Oxygen is supplied this cavity via a spray bar which plays upon the transparent window to assist in defogging. Exhalation passes into a duct at the lower edge of the visor opening and is ducted over the wearers head to the rear 4of the helmet, thereby assisting in cooling the `back .of the wearers head. The oxygen breathing regulator and compensated exhalation valve are located inside the helmet shell as an integral part thereof.

A feature of the present invention is a face seal which automatically adjusts to varying facial widths and contours. An inner frame -designed to generally follow the facial contours is adapted for horizontal outward flexure. The frame is padded with a resilient material, a portion of which is both pneumatically and mechanically loaded against the face by a strip of porous resilient material retained between the padded covering and the frame proper.

A helmet suspension system includes a movable backrest which may be adjusted so as to hold the wearers head forward in the helmet. This improves the visual field of the wearer and, in addition, reduces the dead space in the oral-nasal cavity. The suspension may be adjusted in flight so that the degree of stability may be varied to suit flying situations. Also, comfort of the pilot is considerably improved by periodic adjustments .of the suspension.

A more thorough understanding of the invention may be obtained by a study of the following detailed description taken in connection with the accompanying drawings in which:

FIG. l is a right front perspective view of a protective helmet constructed in accordance with the invention;

FIG. 2 is a left side view of the helmet with portions of the outer shell broken away;

FIG. 3 is a right side View of the helmet in section;

FIG, 4 is a perspective view of the integral oxygen supply and exhaust system;

FIG. 5 is a rear view of the helmet suspension system;

FIG. 6 is a view taken along line 6 6 of FIG. 5;

FIG. 7 is a cross-section view taken along line 7-7 of FIG. 5;

FIG. 8 is an elevational view of a face seal constructed in accordance with the present invention;

FIG. 9 is a perspective view of the face seal of FIG. 8; and

FIG. 10 is a plan View of the face seal of FIG. 8.

Referring now to the figures, a protective flight helmet comprises a shell 10 formed of two halves 11, 12 of hard, penetration resistant material shaped to cover the head of the wearer. A preferred material for the front and rear halves of the shell 10 is a molded epoxy resin and glass cloth laminate. The two shell halves are hinged at the top as shown at 13 to form a clam shell type entry and are keyed together throughout the extent of the joint 14. A positive, automatic lock 15 is provided on each side of the helmet near the bottom edge of the shell to lock the shell halves together.

The shell 10 includes a cut-out 20 for the wearers neck. This neck opening is close fitting with portion 21 of the rigid shell half 11 cupping the wearers chin (FIG. 3), thereby minimizing air scoop effect. Since the neck opening 20 is considerably smaller than the wearers head when the helmet is in position and locked, loss of the helmet during high speed ejection is virtually impossible. The neck opening is preferably padded with a soft eX- truded neoprene sponge edgeroll 22, which in turn is covered with a scuf-resistant covering 23 such as cabretta leather;

The front shell half 11 includes a full-face opening 25 extending above the chin to the brow of the wearer. A

transparent visor 25 comprises a frame 27, preferably formed of fiberglass and epoxy resin retaining an ultraviolet absorbing acrylic plastic window 28. Frame 27 is shaped to follow the exterior contour of the full-face opening 25. Frame 27 is pivotally mounted to the front shell half Il by respective visor pivots 30, 3l (FIGS. l and 2). Visor 26 is lowered from a position above the head of the wearer to a position in front of said fullface opening 25 by pushing downward upon detent button 32 located in the left visor pivot Sli. A pneumatic visor seal comprising a resilient conduit 4i) surrounding the opening 25 is automatically inliated when visor 26 is lowered. As shown in FIGS. l and 4, this seal is connected to an on-off oxygen valve 4I. The valve is located in the right visor pivot 3i) and is opened and closed upon respective lowering and raising of the visor 26. Additionally, valve 4I includes a slide actuator 42 which when pushed downwardly unlocks the visor 26 and shuts off incoming oxygen. The on-off oxygen valve 4i located in the right visor pivot 30 also acts as a lock for the visor in the lowered position. Locking action is also provided by friction of the inflated seal.

An additional tinted visor 33 is also preferably pivoted upon the pivots 30, Si. This tinted visor assembly is light in weight and designed to break away in wind blasts so that no air scoop effect is produced.

A face seal 49 surrounds the interior of the opening 25 and comprises inner and outer light weight fiberglass and epoxy laminated frames 50, 51. In the description which follows, inner means toward the interior of the helmet and outer means toward the exterior thereof. The inner frame member Si) is adapted for surrounding the Wearers face and is formed as a section of a spheroidal Isurface which is, in plan view (FIGS. 8 and 9) broader at the top or forehead portion 52 than at the bottom or chin portion 53. Additionally, the frame t] curves inwardly from the lforehead portion as shown at 54 in FIGS. 2, 9 to accommodate the Wearers Zygomatic arches. The thin fiberglass construction of frame 5I gives it sufiicient resiliency to flex horizontally outwardly as shown by the broken lines 55 of FIG. l0. This flexure of this member in combination with its foam rubber covering described below provides a seal which automatically adjusts to varying facial widths and contours.

The outer frame member 5I has a generally L-shaped cross-section contoured to t the shell 11 proximate the visor opening 25. Frames 5i), 51 are connected by a diaphragm 56 of flexible multi-directional stretch material such as closed cell neoprene sheet. In the embodiment shown, the diaphragm covers the outer surface of frame 51 and serves as the gas tight seal between the frame and the shell half Il. Alternatively, a separate sealing ring may be used therebetween. The diaphragm 56 coversa portion of the inner side of frame 50 las shown 1n FIG. 2.

Inner frame 5G is covered with a iiexible material such as a closed cell neoprene foam pad formed by an inner member 57 aiiixed to and extending entirely around the inner surface of frame 50 and an outer member 58 affixed to the lower portion of both the outer surface of frame 50 and member 57. Flexible members 57, 58 include an inwardly extending portion 59 at the bottom of the face seal which is contoured to fit the chin. This contour may be formed by cutting a wedge-shaped portion from member 57 and abutting the respective ends together as at 110. Outer member 58 supports the abutting ends and provides an additional thickness of material in the chin area.

The interior portion III of pad 57 is not attached to the inner frame 50 but forms a wedge-shaped groove i12 extending around the entire circumference of frame 50. An elongated strip 113 having relatively small cross-sectional dimensions and formed of porous resilient material such as open cell polyurethane foam is aflixed between the interior portion III of pad 57 and the portion of the diaphragm 56 covering the inner frame 50. Strip 113 serves for both pneumatically and mechanically loading the pad portion III in contact with the face. Pneumatic loading is provided by air pressure within the oral-nasal cavity 60 described below, this air passing through the porous material of strip 113 thereby maintaining the inner surface of portion 111 in contact with the face along its entire circumference.

The face seal 49 is shown in FIG. 2 in a relaxed position and in FIG. 3 in the usual compressed position when worn. The face seal 49 rests on the bony structure of the face. It encloses the brow, passes down the sides from the temple to the rear of the jaw and cups the chin. It has been found that a single face seal constructed in the manner described above comfortably and reliably fits the 5th to 95th percentile faces. The seal is self-centering and assists in maintaining stability. A particular advantage of the face seal 49 is that it is attached well forward in the front half 11 of the helmet shell. This provides minimum dead space in the oral-nasal cavity 60 thereby assisting in preventing an increased CO2 concentration therein. In addition, this seal in combination with the adjustable back pad described herein-below provides increased peripheral vision for the pilot.

The space between the face seal and the visor 26 forms an oral-nasal cavity 60. Oxygen is injected into this cavity by a spray bar 61 comprising a tubular member substantially surrounding the opening 25 and having a plurality of longitudinally spaced orifices. The oxygen ejected from the spray bar washes across the transparent Window 23 to assist in defogging. Exhalation from the cavity 60 passes into a duct 62 formed at the lower edge of the visor opening 25 by the outer shell 11 and interior wall member 63 affixed thereto. The exhalation is exhausted through a compensated exhalation valve 64 in the left jaw area into a duct 65 also formed by the outer shell 11 and an inner wall member 66 affixed thereto. This duct joins with a duct 67 extending just above the upper edge of opening 25; duct 67 being formed between outer shell 11 and an inner wall member v68. Wall member 68 includes at least one and preferably several apertures 69 which coincide with apertures 70 formed in the liner 9i) described hereinafter. The exhalation is exhausted through these apertures to the rear of the helmet, thus providing a means for self-Ventilating the helmet interior and in particular assisting in cooling the back of the Wearers head.

Oxygen is supplied the spray bar `61 from a demand oxygen regulator mounted on the inside of the helmet shell 11 as an integral part thereof. A preferred regulator 75 is described and claimed in the U.S. Patent No. 3,076,- 454, I. R. Evans et al. assigned to Robertshaw Controls Company, assignee of the present invention. The regulator 75 in turn is supplied from the one-off valve 41. An external supply of oxygen is connected to this valve via a conduit 76 (FIG. 4). It will thus be apparent that the invention provides a unified helmet and oxygen breathing system. The fully enclosed oxygen assembly shown in the figures significantly reduces the drag effect which is caused by aerodynamic forces on pilot ejection from high speed aircraft. A further advantage of mounting the oxygen regulator on the inside of the helmet is that it provides visor defogging capability in the case of decompression.

The rear shell half 12 includes a suspension member for sizing the helmet to the wearers head, this suspension member comprising a movable back pad 77 (FIGS. 5, 6 and 7). Pad 77 forms the back liner of the helmet and comprises curved fiberglass and epoxy laminated member 78, impact protecting liner 79 of rigid polyurethane foam, and comfort liner 80 of a soft polyester foam covered with fabric. The movable back pad is mounted so that its upright position is maintained while being movable forward and aft. Member 78 is indented at 81 to form a longitudinal horizontal groove in the back side thereof. A pair of vertical straps S2 span the groove and support headed pins S3 which attach to resilient mount 84.

The midpoint of member 84 is attached to the back of rear shell member 12 as shown in FIG. 6 to bias the back pad 77 toward the back wall of rear shell half 12. As shown in FIG. 5, pins 83 engage respective slots 85 permitting the respective ends of resilient member 84 to move with respect to member 80. When this member is moved fore and aft by adjustment knob 86.

Rotation of knob 86 selectively winds or unwinds a flexible cable 87 connected 4to flexible strip 8S. This latter strip is connected to the opposite side of shell 12 and abuts the back of back pad member 77. The strip 88 is free to slide with respect to the back of the member 77 so that the latter member can assume a central position within the helmet, i.e., the back pad member is selfcentering when the helmet is worn. Rotation of knob 86 producing windup of cable 87 in turn causes the entire 'back of the liner to move forward against the force of mount 84 so that the wearers head is held forward in the helmet as shown in FIG. 3. The visual field is thus kept as large as possible. Other advantages of moving the wearers head forward in the helmet are that it improves the face seal and decreases the dead volume in the oralnasal cavity.

The suspension may be adjusted in flight by simply rotating knob 86. The degree of stability of the helmet upon the wearer may thus be varied to suit flying conditions. Also, the comfort of the wearer is considerably improved by periodic adjustments of the suspension.

The remaining interior of the helment comprises a rigid, crushable liner 90 covering the fbrow, crown, back and sides of the wearers head up to the visor opening 25 and the front of the shell An example of a preferred material for this liner is a low density, rigid polystyrene material. This type of linear provides impact protection from side blows and increased helmet stability. Additional lining of the helmet interior is provided at the sides and back with soft polyether foam, covered with fabric, for increased comfort of the wearer. Variable thickness crown pads 91 of the same material are used for vertical location of the helmet upon the wearers head.

The chin area, bel-ow the face seal, may be padded with a resilient, slow-recovery sponge 95. This protects the chin and jaw from frontal loads and assists in stabilizing the helmet.

All types of communication equipment are compatible with the helmet shown in the figures, earphones 100 mounted to the respective sides of helmet shell 11 and microphone 101 mounted in the oral-nasal cavity 60 being shown by way of example.

The manner in which the helmet is used is as follows: The locks are depressed, thus allowing the back shell 12 to be swung upwardly through an angle of approximately 90. The person donning the helmet then moves the front shell 11 into position so that his face is comfortably seated in the face seal 49. The back shell 12 is then swung downwardly and automatically locks to the frontal shell. The visors 26, 33 may be either in the raised or lowered Iposition during donning and doiiing of the helmet. When the helmet is in place with the shell halves locked together, the suspension may be adjusted by rotating knob 86 to translate the backrest 77 forward.

When the visor detent in the left visor pivot 30 is actuated and the clear visor 62 lowered, the on-off oxygen valve ilV will automatically lock this visor down, inflate the visor seal 40 and turn on the supply to the automatic pressure breathing regulator 70. The wearer is thus fully ready for iiying simply by lowering his visor. To remove the helmet, the slide actuator 42 or the on-olf `valve 41 is pushed downwardly. This automatically un locks the visor, shuts off incoming oxygen and exhausts the oxygen in the inliatable visor seal so that the visor 26 may be immediately raised. The lock 15 may then be depressed and the back shell 12 raised upwardly and the helmetV removed from the wearers head.

Although an exemplary embodiment of the invention has been disclosed and discussed, it will be understood that other applications of the invention are possible and that the embodiment disclosed may be subjected to various changes, modifications and substitutions without necessarily departing from the spirit of the invention.

We claim:

1. A protective helmet and unified oxygen breathing assembly comprising an outer, two-piece shell of hard, penetration resistant material shaped to cover the human head, said twopiece shell forming front and rear shell halves hinged together at the top thereof to form a clam shell type entry,

said shell having a close fitting neck opening considerably smaller than the wearers head,

the front shell half including a full-face opening extending abovev the wearers chin to the brow of the wearer,

a rigid, crushable inner lining covering the brow, crown, back and sides of the wearers head to said full-face opening,

a transparent visor conforming to the exterior contour of said full-face opening,

means for pivotally mounting said transparent visor to said front shell half so that said visor may be raised above the wearers head and lowered intn position in front of said full-face opening,

a pneumatic visor seal surrounding said full-face openmeans for automatically inating said pneumatic visor seal when said transparent visor is lowered into position,

a face seal comprising inner and -outer frames,

said inner yframe being padded with a resilient material to adjust to varying facial widths and contours,

said outer frame being affixed to and supported by the internal wall of said front shell half around said full-face opening, and

a iiexible diaphragm between said inner and outer frames,

means affixed within said outer shell means for supplying -oxygen to the oral-nasal cavity formed between said face seal and the transparent visor when said visor covers said full-face opening,

an exhalation valve in communication with said oralnasal cavity, and

a movable inner liner mounted in and supported by said rear shell half,

means supported by said rear shell half for moving said inner liner fore and aft for moving the wearers head forward in the helmet into engagement with the padded inner frame of said face seal, said padded inner frame being moved forward in said front shell into a compressed position to make sealing contact with the wearers face thereby maximizing visual space in said oral-nasal cavity, and minimizing dead volume in said oral-nasal cavity.

2. The protective helmet defined in claim 1 comprisa duct opening into said oral-nasal cavity at the lower edge of said full-face opening, said duct containing said exhaust valve and extending along the inside wall of said front shell half to over said full-face opening and having at least one aperture into said shell above said face seal so that exhalation is exhausted therethrough to self-ventilate the helmet interior.

3. The protective helmet `detined in claim 2 wherein said rigid, crushabl-e inner lining includes an aperture in alignment with the aperture in said exhalation duct.

4. The protective helmet defined in claim 2 wherein said duct and exhaust valveinclude a compensated exhalation valve mounted in the jaw area of said front shell half,

a first duct means extending from said oral-nasal cavity to said exhalation valve, and

a second duct means extending from said exhalation valve to over said full-face opening.

5. The protective helmet defined in claim 1 wherein said movable inner liner includes a curved member having a longitudinal groove in the back side thereof,

a resilient mount between said curved member and the rear Shell half permitting fore and aft movement of said member while biasing same toward the back` wall of said rear shell half,

an adjusting means, and

a flexible member having one end attached to the wall of the rear shell half, a mid portion abutting said curved member and the other end attached to said adjusting means adapted to pull said flexible member against the force of said resilient mount.

`6. The protective helmet defined in claim 5 wherein said exible member is in sliding engagement with said curved member so that the latter member can assume a central position in said helmet regardless of its fore or aft position.

7. The protective helmet defined in claim 1 wherein said movable inner liner includes means for maintaining said liner upright while providing fore and aft movement.

8. The protective helmet defined in claim 1 wherein said inner frame of the face seal has sufficient resiliency to flex horizontally outwardly to automatically adjust to varying facial widths and contours.

9. The protective helmet defined in claim 1 comprising means for both pneumatically and mechanically loading a portion of the material used for padding said inner frame against the wearers face,

said pneumatic and mechanical loading means including a strip of porous resilient material retained between said padded covering and said inner frame, said strip having a surface open to said oral-nasal cavity so that gas passing through said porous material fro-m said oral-nasal cavity maintains the padded surface of said inner frame in sealing contact with the wearers face.

10. A protective helmet comprising an outer shell of at least two pieces, generally shaped to lit the human head, said shell pieces being hinged together so that said pieces may be opened for entry of the wearers head,

one of said shell pieces including a face opening, a transparent visor thereover and a flexible face seal forming an oral-nasal cavity therebetween,

means for supplying oxygen to said oral-nasal cavity.

an exhalation valve in communication with said oralnasal cavity,

said helmet including a movable means for moving the wearers head forward in the helmet into engagement with the face seal, said flexible face seal being moved forward in said one shell piece into a compressed position to make sealing contact with the wearers face thereby maximizing his visual field, improving the face seal and assisting in preventing an increase in CO2 concentration in said oral-nasal cavity.

11. The protective ing means for self-Ventilating the interior of said helmet comprising a ventilation orifice and ducting means connecting said ventilation orifice to said exhalation valve, said ventilation orifice distributing exhalation from said exhaust valve over the wearers forehead.

12. The protective helmet defined in claim 11 comprising:

means for forming said ducting means including a portion of said one shell half and an inner wall member affixed thereto,

helmet defined in claim includ- 13. The protective helmet defined in claim 10 comprising resilient means for mounting said movable inner liner to the rear shell half permitting fore and aft movement of said liner while biasing same toward the back wall of said shell half, and

adjusting means coupled to said movable liner for forwardly moving same against the force of said resilient mount.

14. A facial sealing means for forming an oral-nasal cavity between the wearers face and a transparent visor of a protective helmet, said sealing means including an inner frame adapted to surround the wearers face, said frame being sealably connected to the helmet around the visor,

a flexible, gas tight padding material covering the surface of the frame which abuts the wearers face, and

means for both pneumatically and mechanically loading a portion of said padding material against the wearers face, said pneumatic and mechanical loading means including a strip of porous resilient material retained between said padded covering and said inner frame, said strip having a surface open to said oral-nasal cavity so that gas passing through said porous material from said oral-nasal cavity maintains the padded surface of said inner frame in sealing contact with the wearers face.

1S. The facial sealing means defined in claim 14 wherein said strip of porous material comprises open cell polyurethane foam.

16. A facial sealing means for forming an oral-nasal cavity between the wearers face and a transparent visor of a protective helmet, said sealing means including an inner frame adapted to surround the wearers face, said frame being sealably connected to the helmet around the visor,

a flexible, gas tight padding material for covering the surface of the frame which abuts the wearers face, the exterior portion only of said padding material being aiixed to said frame to form a wedge shaped groove between the interior portion of said material and said frame, said groove extending around the circumference of said frame, and

a strip of porous resilient material retained in said groove for pneumatically and mechanically loading said interior portion of said padding material against the wearers face, said strip having a surface open to said oral-nasal cavity so that gas passing through said porous material from said oral-nasal cavity maintains the padded surface of said inner frame in sealing contact with the wearers face.

17. A protective helmet and unied oxygen breathing assembly comprising an outer, two-piece shell of hard, penetration resistant material shaped to cover the human head, said twopiece shell forming front and rear shell halves hinged together at the top thereof to form a clam shell type entry,

said shell having a close fitting neck opening considerably smaller than the wearers head,

the front shell half including a full-face opening extending above the wearers chin to the brow of the wearer,

a rigid, crushable inner lining covering the brow, crown, back and sides of the wearers head to said full-face opening,

a transparent visor conforming to the exterior contour of said full-face opening,

means for pivotally mounting said transparent visor to said front shell half so that said visor may be raised above the wearers head and lowered into position in front of said full-face opening,

a pneumatic visor seal surrounding said full-face openlng means for automatically inilating said pneumatic visor seal when said transparent visor is lowered into position, a face seal comprising inner and outer frames,

said inner frame being padded with a resilient material to adjust to varying facial widths and contours, said outer frame being aixed to and supported by the internal wall of said front shell half around said full-face opening, and a flexible diaphragm between said inner and outer frames, means aixed within said outer shell means for supplying oxygen to the oral-nasal cavity formed between said face seal and the transparent visor when said visor covers said full-face opening, means for both pneumatically and mechanically loading a portion of the material used for padding said inner frame against the wearers face, said pneumatic and mechanical loading means including a strip of porous resilient material retained between said padded covering and said inner frame, said strip having a surface open to said oral-nasal cavity so that gas passing through said porous material from said oralnasal cavity maintains the padded surface of said inner frame in sealing contact with the wearers face, a duct opening into said oral-nasal cavity at the lower edge of said full-face opening, said duct extending along the inside wall of said front shell half to over said full-face opening and having at least one aperture into said shell above said face seal so that eXhalation is exhausted therethrough to self-ventilate the helmet interior, said rigid crushable inner lining including an aperture in alignment with said aperture in said exhalation duct, a movable inner liner mounted in and supported by said rear shell half, and means for moving said inner liner fore and aft for moving the wearers head forward in the helmet to provide sealing contact with said face seal, maximum visual space in said oral-nasal cavity, and minimum dead volume in said oral-nasal cavity, said movable inner liner including a curved member having a longitudinal groove in the back side thereof,

a resilient mount between said curved member and the rear shell half permitting fore and aft movement of said member while biasing same toward the back wall of said rear shell half,

an adjusting means, and

a flexible member having one end attached to the wall of the rear shell half, a mid portion abutting said curved member and the other end attached to said adjusting means adapted to pull said exible member against the force of said resilient mount.

18. A protective helmet including a transparent visor comprising:

a face seal connected to the helmet adapted to surround the wearers face and dene an oral-nasal cavity between the wearers face and the visor;

means for spacing the wearers head from portions of the helmet interior to dene a chamber in contact with substantial portions of the top, back and sides of the wearers head;

means for supplying oxygen to said oral-nasal cavity,

and

means for directing the exhalation gases from the oralnasal cavity into said chamber above the wearers head and down and around the wearers head to ventilate the chamber.

References Cited UNITED STATES PATENTS 2,579,942 12/1951 MacLean 128-142 2,861,272 11/1958 Stuart et al 2-6 2,935,985 5/1960 Andrews et al 12S-141 3,028,602 4/ 19612 Miller 2 6 3,130,415 4/1964 Colley 2-6 3,149,632 9/ 1964 Colley 128-142 RICHARD A. GAUDET, Primary Examiner.

W. E. KAMM, Examiner. 

10. A PROTECTIVE HELMET COMPRISING AN OUTER SHELL OF AT LEAST TWO PIECES, GENERALLY SHAPED TO FIT THE HUMAN HEAD, SAID SHELL PIECES BEING HINGED TOGETHER SO THAT SAID PIECES MAY BE OPENED FOR ENTRY OF THE WEARER''S HEAD, ONE OF SAID SHELL PIECES INCLUDING A FACE OPENING, A TRANSPARENT VISOR THEREOVER AND A FLEXIBLE FACE SEAL FORMING AN ORAL-NASAL CAVITY THEREBETWEEN, MEANS FOR SUPPLYING OXYGEN TO SAID ORAL-NASAL CAVITY. AN EXHALATION VALVE IN COMMUNICATION WITH SAID ORALNASAL CAVITY, SAID HELMET INCLUDING A MOVABLE MEANS FOR MOVING THE WEARER''S HEAD FORWARD IN THE HELMET INTO ENGAGEMENT WITH THE FACE SEAL, SAID FLEXIBLE FACE SEAL BEING PRESSED POSITION TO MAKE SEALING CONTACT WITH THE WEARER''S FACE THEREBY MAXIMIZING HIS VISUAL FIELD, IMPROVING THE FACE SEAL AND ASSISTING IN PREVENTING AN INCREASED IN CO2 CONCENTRATION IN SAID ORAL-NASALL CAVITY. 